The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art.
Planetary gear assemblies are remarkably versatile and adaptable devices. Various motor vehicle driveline components such as transmissions, differentials and transaxles make frequent and common use of planetary gear assemblies. Typically they are utilized either singly to provide a speed reduction and torque increase or arranged in tandem and associated with clutches and brakes that interconnect or ground various elements of the planetary gear assemblies to provide multiple speed reductions and torque multiplications.
A simple planetary gear assembly comprises a centrally disposed sun gear, a planet gear carrier disposed generally about the sun gear and a ring gear disposed about the carrier. A plurality of planet gears rotatably mounted on shafts in the carrier engage both the sun and the ring gears.
There are, of course, many engineering issues regarding the design and manufacture of planetary gear assemblies. One involves the manner by which the planet gear shafts are retained or secured to and within the planet gear carrier. One approach is to provide small bores through the shaft and carrier that may be aligned and through which a retaining pin may be inserted. Another approach involves deforming by, for example, staking, the pinion shaft to the carrier. Both of these approaches require suitable shaft adjacent regions of the carrier which may either receive the pin or the deformed region of the shaft and thus may not be suitable in many instances.
Another engineering issue relates to lubrication. In certain configurations and in certain vehicle speed ranges, the rotational speed of the planet or pinion gears of a given planetary gear assembly may be quite significant, i.e., many thousand r.p.m. The rotational speed of the planet gear carrier may also be quite high. High planet or pinion gear speeds are not problematic per se but they do require sufficient lubrication not only to lubricate the pinion-bearing-pinion shaft interface but also to carry off heat generated by such high speed rotation at the interface.
The present invention is directed to providing an improved retainer which not only retains pinion shafts in a planet gear carrier but also maintains their angular orientation which provides improved bearing lubrication.